Serbian was valued at under £5m in move to Benfica as part of David Luiz purchase three years ago but outlay is offset by £18m sale of Kevin De Bruyne to Wolfsburg

Nemanja Matic is due to undergo a medical on Tuesday ahead of completing a return to Chelsea .

The midfielder was valued at less than £5 million when he left Stamford Bridge as part of the deal that took David Luiz to Chelsea from Benfica.

Just three years later, Chelsea are poised to re-sign Matic for around £22 million and, barring any hitches, he could replace Luiz in the team to face Manchester United on Sunday.

Jose Mourinho was keen to land a new central midfield enforcer and the Chelsea manager has no qualms about bringing back Matic, particularly as he did not initially sign or sell the Serbian.

Chelsea will point to the fact that Matic has developed into a much better player at Benfica than the one who was struggling to get games at Stamford Bridge.

They will also argue that the only way to get Luiz was to allow Matic to go to Portugal as part of the £23.5 million deal. Luiz played in central midfield in the victory against Hull City, where Matic will be expected to establish himself alongside Ramires.

Chelsea’s financial hit on Matic has been offset in some part by the £18 million they have collected from German club Wolfsburg for Kevin De Bruyne, who joined the Blues for £7 million from Genk two years ago and made nine senior appearances.

Sources in Portugal claim that Matic will sign an initial contract with Chelsea to 2017, but that may contain the option of a further year. The 25-year-old had a £37 million buy-out clause in his Benfica contract, but financial pressures meant that the Portuguese club could not hold out for that fee.

Matic initially joined Chelsea for just £1.5 million from MFK Kosice in 2009 and he played three senior games before being loaned out to Vitesse Arnhem and then sent to Benfica as part of the Luiz deal.

Ahead of the Europa League final last season, in which Matic played for Benfica against Chelsea, Branislav Ivanovic praised the improvement in his Serbian international team-mate.

“There is a lot of positive news about Nemanja Matic and the way he plays, he is improving a lot,” Ivanovic said. “When he was at Chelsea, you saw he has the qualities to be a top player, but he needed practice, he needed to play and he decided the best option for him was to move to Portugal and to move to one of the biggest clubs there.

“Now he is playing maybe the best football of his career. In Portugal, he has improved his defensive ways a lot, and his aggressiveness. And he has great vision forward. Benfica put trust in him because Axel Witsel left for Zenit St Petersburg and Javi García left for Manchester City as well – two key players for them – and Matic got the chance to play more and he used the chance.”

De Bruyne will sign a contract to 2019 with Wolfsburg, having only managed two Premier League starts under Mourinho and been criticised for a poor display in the Capital One Cup clash against Swindon Town.

Mourinho has boldly warned Chelsea’s Premier League opponents that his team will not peak until next season and 2015-16, but will then replicate the wave of success that the club has enjoyed over the past decade.

Despite the obvious absence of a prolific striker, Chelsea remain only one point behind title favourites Manchester City and, should they maintain that challenge, Mourinho believes that this squad’s collective development will accelerate significantly.

Chelsea have won 11 major trophies since Mourinho began his first spell at the club in 2004 and he says that the foundations are being laid for a similar period of sustained success.

“We are there and fighting for the top positions, we will see if we can fight for the title,” Mourinho said. “It’s important we do because it accelerates the development of the players, it brings to their lives something new, to have the responsibility of having to win every game.

“Normally I’d say the second and third seasons together are the best ones. But it is Chelsea’s mentality, my DNA, to try to challenge now. I built a Chelsea team that lasted seven-eight years and was in place to fight for titles even after my departure, I know that I’m going to do the same.”

Mourinho has also again reiterated an intention to stay at Chelsea for as long as owner Roman Abramovich wants, saying: “I’m not here thinking about my next move because I don’t want to have a next move. I will have a next move if and when Chelsea decides it’s time for that.

“I’m not chasing new experiences, trying to find where I like it more, where I can make new things for my career – no. It’s a completely different perspective.

“I’m here to stay. I belong to Chelsea, Chelsea belong to me. I gave a lot to Chelsea in the past but they also gave a lot to me. This is a different professional relationship.”